It is known in the art to produce toothed articles, such as bevel and hypoid gears, with cutting tools comprising a head portion in which a plurality of cutting blades are positioned, for example, stick-type cutting blades manufactured from bar stock such as shown in U.S. Pat. No. 4,575,285 to Blakesley.
In the type of cutting tool mentioned above, it is customary to provide a circular cutter body having a plurality of slots extending inwardly a predetermined distance from the periphery of the cutter body for receiving and positioning cutting blades in the cutter body. In many instances, extending about the periphery of the cutter body is a clamping ring (or locking ring) which is secured to the cutter body and in which is mounted means to clamp one or more cutting blades in each of the positioning slots. Cutting tools including a clamping ring and blade clamping means can be seen, for example, in U.S. Pat. Nos. 4,621,954 to Kitchen et al.; 3,760,476 to Kotthaus; 4,093,391 to Bachmann et al.; or 4,197,038 to Hipp et al.
The clamping ring is secured to the cutter body in many instances by welding or heat shrinking. Although these methods represent a very secure manner by which to attach the clamping ring to the cutter body, they also introduce significant heat into the cutter head which can distort the cutting blade positioning slots or warp the cutter head, thus introducing dimensional inaccuracies such as runout into the workpiece being machined.
Unacceptable workpiece quality may also be caused by inadequate clamping of the cutting blades in the cutter head. Cutting blades that are not securely clamped will lose their precise positioning in the cutter head thereby contributing to workpiece runout as well as poor surface quality of the tooth flanks. Some clamping arrangements provide for only a single source of clamping force applied to a cutting blade which affords the opportunity for movement of the cutting blade under cutting loads. Other clamping arrangements, while providing more stable clamping systems, are quite awkward due to the presence of multiple clamping screws or a large number of components. Still other clamping systems make no provisions for retaining the clamping mechanism in the cutter head blade slot when no blade is present.
It is, therefore, an object of the present invention to provide a clamping ring which can be secured to a cutter body while avoiding the detrimental effects due to heating of the cutter head.
It is an additional object of the present invention to provide a cutting blade clamping system which more securely holds a cutting blade in its proper position in a cutter head.
Another object of the present invention is to include precise mounting surfaces in a cutter head that provide improved seating of a cutting blade in the positioning slots of the cutter head.